Previously known as abdominal epilepsy or abdominal migraine, Cyclic Vomiting Syndrome (CVS) is a chronic condition characterized by recurrent, severe, stereotypic episodes of nausea and vomiting lasting anywhere from hours to days. Between attacks, the child is asymptomatic and neurologically normal.

The average age at onset is 3 to 7 years, although it has been reported in children as young as 6 months. Originally described in Samuel Gee in 1882, CVS was thought to occur only in children, but now adult cases are being recognized. Incidence is about .04 percent in the population, with a male-to-female ratio of about 50/50 and a median onset age of about 4.8 years. CVS is likely a form of migraine, since it responds to similar management and is often associated with a family history of migraine.

Episodes can be mild to severe, with some children requiring hospitalization for re-hydration and pain control. Attacks, which tend to resemble previous episodes, are often diagnosed as recurrent bouts of “gastroenteritis.” The delay in diagnosis is typically 2.7 years. During an attack, the child may be pale and anorectic and complain of abdominal pain and headache, making it hard to differentiate from other causes of abdominal pain. The key is the repetitive history, with periods of being completely asymptomatic in between. Attacks tend to come on suddenly, with little warning, often in the early hours of the morning, awakening the child. Children may also complain of dizziness, photophobia and diarrhea during an episode. The condition follows a four-part pattern: prodrome (often short), the actual episode, recovery, and a symptom-free interval. There can be numerous triggers including the child being over-tired, over-excited, sick, premenstrual or stressed the day before. Children tend to have their own unique triggering events.

The routine abdominal pain work-up is usually normal. Tests such as CBC, electrolytes, sedimentation rate and abdominal imaging typically are unremarkable. Occasionally, a KUB will reveal constipation and/or an ileus.

Change in the patterns of attacks, especially increasing severity or shortened asymptomatic intervals

CVS has no definitive anatomic or laboratory diagnostic studies, aside from the history. A family history of migraine is present in 80 percent of affected children. About 27 percent of these children progress to have classic migraine symptoms as adolescents. The etiology is unknown but two DNA polymorphisms (16519T and 3010A) occur in high frequency in pediatric patients.

Approach to Diagnosis and Management

More than 90 percent of children who meet the following criteria will ultimately have a diagnosis of CVS:

The diagnosis is usually made on the basis of the history and presentation

At least five attacks in a given interval or three within a six-month period

Episodes of intense nausea and vomiting lasting hours to days with a week between attacks

Stereotypical pattern in symptoms

Vomiting four or more times per hour

Return to normal “baseline” between attacks

No other etiology for the attacks

CVS is likely a form of migraine, since it responds to similar management and is often associated with a family history of migraine.

Illustration by Joshua Emerson

If any of the “red flags” described below are present, the work-up should be expanded to include surgical and non-surgical causes of chronic severe abdominal pain, including volvulus, obstruction, adhesions, esophagitis or pancreatitis.

Episodes that result in acidosis or are triggered by fasting or high-protein intake should be evaluated for an inborn error of metabolism or possible mitochondrial disease. In these cases, determination of plasma amino and urine organic acids, lactate/pyruvate ratio, and anion gap are indicated. Any abnormal neurological finding would warrant work-up of CNS lesions or seizures, including imaging such as CT or MRI.

Management

The approach is primarily supportive, but can be divided into prevention (avoiding triggers), prophylaxis (decreasing or preventing episodes), and aborting early attacks. Management of the acute episodes seeks to minimize duration, relieve symptoms and prevent hospitalization. Each child requires an individualized treatment plan that fits his or her symptoms and life style. If the attacks are rare, the focus will be on aborting or decreasing severity of the attacks. Frequent attacks (several per month) will require prophylaxis as well as a plan for managing the acute attacks.

As with migraine, prevention of CVS is based on avoiding the usual triggers. These include being over-tired, changes in altitude, long car trips, over-excitement or stress. Certain foods such as chocolate, cheese, artificially sweetened beverages and MSG, as well as caffeine withdrawal, can act as triggers. An elimination diet may help. Ensuring the child gets enough regular sleep and exercise are simple measures that can also be effective.

Medications

Primary medications commonly used for prevention are antihistamines and serotonin receptor antagonists such as hydroxyzine (Atarax, Vistaril) and cyproheptadine (Periactin). These are given at night to avoid daytime drowsiness and can be titrated up slowly. Second-line medications include beta blockers such as propranolol. Children over 5 years are candidates for tricylic antidepressants. Third-line drugs include topiramate (Topomax) and valproic acid (Depakote) and should be managed with the help of a pediatric neurologist. L-carnitine and co-enzyme Q have also been used as adjuncts.

Avoiding full-blown attacks or abbreviating episodes requires the early administration of such medications as sub-lingual ondansetron (Zofran) or triptans (Imitrex), although triptans is not recommended for younger children. If the child becomes dehydrated or the attack continues and/or escalates, emergency care is usually required. Parents need guidelines on when to stop home treatment and seek further help. Physicians should provide patients with a letter that they can show to emergency room doctors who may not be aware of the condition.

In the ER, the priority is to administer glucose containing IV fluids (D5½ normal saline at 1½ maintenance; consider normal saline 10-20 ml/kg bolus initially, depending on degree of dehydration) along with antiemetics (IV ondansetron 0.1 mg/kg up to 4 mg), sedatives (IV lorazepam 0.05 mg/kg), PPIs (esomeprazole IV 1 mg/kg) and appropriate analgesics (IV ketorolac 0.5 mg/kg up to 15 mg). Higher doses of these medications are considered for refractory cases. If the child can sleep, this may end the attack, and often is enough to be able to send the child home. Some attacks are so prolonged, they almost always require hospitalization. Again, the pattern of the individual child – for example, if he or she also suffers from asthma – will likely dictate the physician’s approach. The key is administering fluids and medication quickly and placing the child in a quiet, dark room.

Summary

CVS is an idiopathic functional disorder of vomiting and nausea very likely related to migraine. It has been rarely associated with mitochondrial and neuroendocrine disorders in some children and may be associated with anxiety and panic disorders in adults. About one-third of children will progress to more typical migraine as adults, but most will outgrow it. It is important to remember this syndrome when confronted with a child experiencing repeated episodes of nausea and vomiting.